Authored by: Dr. Lindsey, DVM
You may have known that babies have open fontanelles when they are born but did you know that puppies do as well? Open fontanelles are also known as soft spots in the skull. They are typically seen in small or toy breed dogs such as Chihuahuas or Pomeranians. In Chihuahuas these soft spots are called moleras and are part of the breed standard. Most of the time these soft spots will close by the time the puppy is 9-12 weeks old.
Open fontanelles are openings in the skull between the growth plates. As a puppy grows the growth plates in the skull fuse shut and there is no longer a soft spot. Sometimes these fontanelles don’t close like they should and are called persistent open fontanelles. The diagnosis of an open fontanelle is usually made on physical exam by the veterinarian during the puppy’s first vet visit. The veterinarian will monitor the open fontanelle at each puppy visit. If it doesn’t close by the time the puppy is about 3-4 months old, it’s considered a persistent open fontanelle. Persistent open fontanelles are caused by a genetic abnormality or an underlying brain condition like hydrocephalus. Even if a puppy has a persistent open fontanelle, it’s usually not concerning unless the puppy gets a head injury or has hydrocephalus. Unfortunately, there is no treatment for an open fontanelle. Because this problem is considered a genetic abnormality, these puppies should not be bred.
Dr. Lindsey graduated from Colorado State University in 2009 and works in general practice, shelter medicine, and more recently as a civilian contractor veterinarian for the Army. She is also certified in acupuncture and resides in Palm Springs, CA.